Kant’s avowed commitment to the basic principles of Leibniz’s metaphysics is evident throughout the critical project and stated explicitly in the Prize Essay. However, it is not until the Critique of Judgment, wherein Kant recognizes that Judgment operating in its reflective mood can engender synthetic a priori claims, that Kant is fully capable of appropriating the basic tenets of Leibniz’s metaphysics. This paper examines Kant’s treatment of Leibniz from the perspective of the Critique of Judgment. It is argued that from this vantage point the metaphysics of Leibniz is viewed as fundamental for Kant’s critical project. Moreover, it is argued that it is not until the retrieval of Leibniz’s metaphysics that Kant has a basis for seeking the unity of pure and practical reason